TB 9-4920-451-24
b. Adjustments
(1) Set MEGOHMMETER OFFSET trimmer screw (fig. 1) for meter indication
that is the same value as stamped above S8 switch (fig.1) (R).
(2) Set MEGOHMMETER GAIN (fig. 1) until meter agrees with value stamped
a. Deenergize and disconnect all equipment.
b. Annotate and affix DA label/form in accordance with TB 750-25.
CALIBRATION PROCESS FOR
GULL AIRBORNE INSTRUMENTS, MODEL GTF-4
13. Preliminary Instructions
a. The instructions outlined in paragraphs 13 and 14 are preparatory to the
calibration process. Personnel should become familiar with the entire bulletin before
b. Items of equipment used in this procedure are referenced within the text by
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. Additional
maintenance information is contained in the manufacturers' manuals for this TI.
d. Unless otherwise specified, all controls and control settings refer to the TI.
WARNING
HIGH VOLTAGE is used or exposed during the performance of
this calibration.
DEATH ON CONTACT may result if
personnel fail to observe safety precautions.
REDUCE
OUTPUT(S) to precautions.
REDUCE OUTPUT(S) to
minimum after each step within the performance check where
applicable.
a. Remove top protective cover as required for adjustments.
b. Connect TI to 115 V, 400 Hz, using cables supplied with TI.
c. Set POWER ON/OFF switch to ON and allow at least 30 minutes for warm-up
and stabilization.